Polaris 280 not moving

I have basically rebuilt my 280 Polaris last year. Recently is have quit moving. 1. I am getting plenty of water pressure coming out of the side of the pool, which is indicated after I unscrewed the hose at the inline filter.

The tail does not have any water going through it and does not move. also the the polaris if not moving, however I am getting pressure and a good stream of water through the backup valve.

What would be the mostly likely piece that needs to be replace??? I was thing the feed pipe!

Thanks,

Rick